1. Field of the Invention
This invention relates to disk head assemblies for supporting read/write heads adjacent rotating disks in disk drives and more particularly, to a swage ring for attaching a load beam assembly to a head actuator arm.
2. Description of the Prior Art
Disk drives typically include a stack of spaced apart, concentric magnetic storage disks mounted on a common shaft, and an actuator arm assembly encased within a housing. The actuator arm assembly, also called a head stack assembly (HSA), comprises a plurality of arms extending into spacing between the disks. Mounted on the distal end of each arm is a resilient suspension assembly to which is attached an air bearing slider, the combination of which is referred to as a head gimbal assembly (HGA). Included in the suspension assembly is a load beam, which is mounted at one end to the actuator arm by means of a base plate, and a flexure which is attached to the other end of the load beam and pivotally supports the slider on a gimbal that keeps the slider suspended in a horizontal plane on the disk surface regardless of any motion of the load beam.
The load beam provides the resilient spring action that biases the slider toward the surface of a magnetic recording disk, while the flexure provides flexibility for the slider. A thin film or other magnetic transducer is deposited or otherwise attached at the rearward end of the slider to read or write on the magnetic disk.
In the prior art, the actuator arm and load beam elements of the head stack assembly are connected end to end by a base plate which includes a flat flange portion and a cylindrical hub portion or boss. In assembling the head stack, the hub is inserted into a load beam boss hole and the flange portion is welded to the load beam. The hub is then inserted into an actuator arm boss hole.
Using a swage machine, a swage ball is driven through the hub. The swage ball exerts pressure on the hub which expands (swages) into the boss hole in the actuator arm. The expanded hub rigidly connects the hub and attached load beam to the actuator arm boss hole. The expanded hub creates a very tight friction fit against the sides of the boss hole. To ensure a tight fit, the length of the hub is such that sufficient contact exists between the outer portion of the hub and the inner portion of the boss hole. As the hub plastically deforms, it hardens, which is desirable for maintaining a press fit in the actuator arm boss hole.
Because the load beam is welded to the flange portion of the base plate and the flange is soft from annealing, the flange deforms easily, resulting in fluctuations in the load beam that is welded to the flange. As the disk drive industry moves to nano and pico form factors, the thickness of the base plate becomes a more significant factor in the overall stack height of the head stack assembly.
It is therefore an object of this invention is to provide a new base plate which will result in a lower stack height of a head suspension assembly.